This application relates generally to drainage structures and associated hardware, and more specifically to an improved contaminant-absorbing filter insert system for use in connection with new or existing water drainage inlets to collect drainage water contaminants such as hydrocarbons and the like while permitting the undisturbed passage of the water.
Drainage structures such as drain inlets for sidewalks, roads and parking lots are well known and in widespread use. Such structures generally provide a path for the removal of rainwater, irrigation water, or the like that would otherwise accumulate on the ground surface. Water thus drained from the surface by these structures is usually carried to a lake, stream or other body of water. Over time, undesirable and sometimes harmful chemical materials, e.g., oil, fuel, antifreeze and the like, collect on the ground surface and can be transported by the drainage system to contaminate these bodies of water.
Drainage structures are also commonly used in indoor facilities, including automotive service areas, parking structures, industrial shops, restaurants, and residential basements and garages. Hydrocarbons and other chemicals are often deposited on the ground during commercial activities at, for example, automotive service and industrial facilities. To a lesser extent, contaminants accumulate on the ground in residential as well as commercial parking structures. Upon surface cleaning, these chemicals are subsequently transported along with the drainage water as with street or parking lot drains. Unless filtered out of the drainage water, contaminating material is carried with the drainage water to the ultimate drainage location.
Prior art filtering devices extract contaminants through the placement of an insert into a storm basin. For example, the Barella device (U.S. Pat. No. 5,720,574) is a square trough-shaped filter insert device for placement into a storm drain basin. Filtration material is placed above a perforated bottom surface of the trough. Run-off water contacts the filtration material; contaminants are filtered out and the filtered water passes through the perforated bottom surface and through to the remainder of the water-directing system. However, some of the drainage water is able to enter the device and pass down its outer wall and through the perforated bottom surface, such that it avoids substantial contact with the filter means and thereby escapes filtration.
Accordingly, a need exists for a greater degree of filtration of hydrocarbons and other contaminants from drainage water, preventing environmental damage while facilitating the economical and functionally efficient drainage of run-off waters.